In the field, e.g. in the course of so-called closed mud or other drilling fluid circulation processes, e.g. in Managed Pressure Drilling (MPD), underbalanced drilling, etc., use is made of rotating control devices (RCDs) having internal sealing elements. Examples thereof are e.g. disclosed in U.S. Pat. No. 8,347,983.
In U.S. Pat. No. 8,347,983 a method for sealing and controlling fluid pressure in an annular fluid passageway in a wellbore related process is disclosed. In the method a fluid, drilling mud, passes through the annular fluid passageway around a drilling tubulars string. Use is made of an annular fluid passageway sealing device, which sealing device comprises:                a housing,        a chamber within said housing,        a lower chamber end member delimiting said chamber at a lower end thereof,        an upper chamber end member delimiting said chamber at an upper end thereof,wherein the lower and upper chamber end member are each provided with an opening therein, which openings are aligned on an axis of the sealing device and are dimensioned so that the drilling tubulars string passes along said axis through said chamber and said chamber end members,wherein the housing is provided with:        an inlet in communication with said chamber to introduce liquid into said chamber,        an outlet in communication with said chamber to discharge liquid from said chamber,wherein further use is made of a liquid pump that feeds liquid into said chamber via said inlet, e.g. circulates liquid through said chamber via said inlet and outlet,wherein the liquid within the chamber is in direct contact with the drilling tubulars string passing through the chamber.        
In U.S. Pat. No. 8,347,983 the introduction of liquid into the chamber and/or the circulation through said chamber, aims to transfer some of the drilling mud pressure that is exerted onto the lower chamber end member, or lower sealing element to the upper sealing element or elements, so that a load sharing of the lower and upper end members is achieved.